CREATE TABLE Exam
    (ExamDateTime   DateTime   NOT NULL,
     RoomNo   CHAR(5)   NOT NULL,
     Supervisor   CHAR(50),
     TotalExaminee   INT,
     ActualExaminee   INT,
     CHECK (TotalExaminee>=ActualExaminee)
     PRIMARY KEY (ExamDateTime, RoomNo),
     FOREIGN KEY (Supervisor)  REFERENCES  Supervisor (Supervisor)
     FOREIGN KEY (RoomNo)  REFERENCES  Room (RoomNo)
     );